EFFICIENT COMBUSTION: More efficient diesel engines for automobiles are making a comeback in the U.S., thanks to new technologies to reduce soot.
Image: flickr/joeszilvagyi
Gone are the days of riding in the family station wagon, inhaling smelly, sooty fumes from a noisy diesel engine.
Diesel engines have always been more efficient than their gasoline counterparts, but over the last decade, the autos and the fuel they run on have had to come a long way to shed their dirty image. Today, diesel cars offer Americans another fuel-efficient vehicle option that could also ease the pain at the pump.
"The great thing about diesel is that it's coming in at the right time," said Allen Schaeffer, executive director of the Diesel Technology Forum. "It's proven itself as a technology, and it has the credentials to compete with policymakers and customers that want to drive a car that's good for the environment and low in carbon dioxide emissions."
Heavy-duty diesel engines found in big trucks, machinery and agricultural equipment have long been the workhorses of the American economy, contributing hundreds of billions of dollars to the country's gross domestic product each year. Diesel cars, however, make up about 1 percent of new car sales in the United States.
But recent regulatory and technological advancements at a time of high gas prices have spurred a revival in the U.S. diesel passenger car market.
According to sales information compiled by Baum & Associates and HybridCars.com, U.S. sales of clean diesel autos increased 39.6 percent last month over March 2011. Diesel auto sales also went up 35 percent in just the first quarter of 2012.
With more clean diesel cars set to hit the market, the trend is expected to continue.
"There's still a perception from the past where in consumers' minds, diesel engines are for trucks or are dirty and stinky," said Torsten Karnahl, general manager for product strategy at Volkswagen, which recently upped production of the diesel-powered Passat to meet rising demand. "But that's just not the case anymore, and customers are now realizing it."
GM's earlier attempt faltered
To improve air quality and cut down pollution from the nation's existing fleet of 11 million diesel engines, U.S. EPA announced $20 million in grant funding yesterday to support clean diesel projects and another $9 billion through direct state allocations.
While diesel cars are cleaning up their act, they have endured a bumpy road since they were first introduced to the United States in the late 1960s, in a sector dominated by the European brands Volkswagen and Mercedes.
U.S. auto manufacturers dabbled in the diesel auto industry during the oil embargo in the late 1970s, when there was a strong push to bring more efficient vehicle technologies to market. In an attempt to roll out a new product quickly, General Motors ended up creating a loud, unreliable car that would turn the American public off diesel for decades.
Europe, meanwhile, did not give up on diesel automobiles. European car companies turned diesels from old clunkers into peppy rides. Thanks also to a fuel tax on gasoline, diesel cars in Europe have been steadily catching up to their gasoline counterparts. Over the last decade, diesel passenger cars accounted for more than half of all new sales in Europe, according to Schaeffer.
Diesel technology in the United States today has also been transformed, and stringent emissions standards set by EPA in 1999 have made diesel engines more than 90 percent cleaner.
The introduction of ultra low-sulfur diesel fuel in late 2006, which cut down harmful sulfur emissions by 97 percent, also gave manufacturers an opportunity to reconsider how diesel cars would fit into their strategic plans for the U.S. market. Both government and industry leaders have described the new fuel as a "game changer."
Now, U.S. automakers are getting back in the diesel game.
GM tries again with a small diesel
"We're definitely seeing a niche market that's growing ... and that's a niche that we've decided to play in," said Tom Read, powertrain spokesman for Detroit-based General Motors.
Earlier this year, GM announced it would draw on European expertise to develop a diesel-powered version of the popular Chevrolet Cruze, set to hit showrooms in 2013. Down the line, GM also plans to offer a diesel version of the Cadillac ATS.
"I think we're the first domestic automaker to say that we'll offer a small displacement diesel in a passenger car, and I think that reflects the push for innovation in propulsion systems that GM is willing to get into," Read said.
The outlook on diesel cars in the United States looks bright.
The sticker price on a diesel car is still $2,000 to $3,000 higher than on a comparable gasoline vehicle. But today's high gasoline prices mean U.S. diesel owners can enjoy short payback periods and even some additional savings. Diesel cars are also prime candidates to help meet the Obama administration's proposed 54.5 mpg fleetwide fuel economy standard by 2025.
"From an engineering standpoint, the diesel fuel and the way we use it allow us to be more thermodynamically efficient," said Margaret Wooldridge, a professor of mechanical engineering at the University of Michigan.
Diesel engines have a higher compression ratio than gasoline ones do, and more compression means more power out of the same amount of fuel, she said.
With the addition of particulate filters and nitrous oxide (NOx) catalytic converters to help meet EPA clean air regulations, new diesels are also just as clean as gasoline cars. In a recent study, researchers found that trucks in compliance with the 1999 EPA standards produced 95 percent less particulate emissions and 98 percent less NOx emissions.
"What's next for diesel? It's about taking what diesels currently have and enhancing it," said Byron Bunker, a director in the EPA Office of Transportation and Air Quality. "It's going to be the same story: Improve the particulate filter, make your NOx catalyst better, make your electronics better, and [the vehicle] will get cleaner and cleaner."
There is definitely still room for improvement.
Better engines for the climate
On average, about 85 percent of the particle matter emitted from diesel trucks is black carbon, said Christopher Frey<, a professor of environmental engineering at North Carolina State University.
"That carbon has certain physical properties where it tends to absorb infrared energy, which is part of the greenhouse effect," he said. "These particles also tend to be very small and can be carried a long distance in the air."
Studies show that deposits in the polar region could be linked back to trucks in the Americas, Frey said. Those deposits make snow grayer, causing it to absorb more sun and consequently melt faster.
Scientists are still trying to develop technologies to further reduce fine particulate matter, which can also have negative effects on human health (ClimateWire, April 23).
But in terms of long-term consequences, diesel engines are better for the climate than a gasoline-powered car, said Katsumasa Tanaka, scientific researcher at ETH Zürich university in Switzerland.
"When you look at the carbon dioxide emissions per kilometer driven, diesel has about 10 to 15 percent higher fuel efficiency than a gasoline engine," said Tanaka, who led a study published in Environmental Science & Technology last month on the climate effects of gasoline versus diesel cars in line with European emissions standards.
The application of hybrid powertrains and renewable fuels on diesel platforms will further reduce the vehicles' greenhouse gas emissions and could breathe still more life into what was a very hazy U.S. industry not long ago.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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17 Comments
Add CommentThey also have superb low-rpm torque and overall drivability. Here's a friendly challenge to Diesel doubters: drive a modern one and you'll see.
Reply | Report Abuse | Link to thisOf course we now get diesel hybrids in Europe.
Reply | Report Abuse | Link to this"The outlook on diesel cars in the United States looks bright.'
Reply | Report Abuse | Link to thisNo it isn't. Why this pollyanish line? Diesal cars will remain DEAD in North America. As for the $3000 extra being recouped...not in your dreams. The difference in fuel is minimal...insurance is more and maintenance is more. No diesal vehicle can begin to touch the lifetime economy of a Toyota Corolla, Honda Civic, etc.
And of course those wonderful particulate filters, in a nutshell if you live in a city and make journeys of less than 15 miles you will be charged about £1500 ($2250) every year for a new one.
Reply | Report Abuse | Link to thisManual transmissions. Ford and VW/Audi use a dual mass flywheel to "smooth" out vibrations etc. The adhesive yes they use adhesive to join them breaks up either taking out your clutch or gearbox.
People often ask me "what car should I get".
Long uninterrupted journeys, diesel; city livers, short and stop start, petrol (gasoline).
Personally I think the future is Hydrogen or a diesel generator running at constant revs with an electric motor powering each wheel.
They cost more up front, the mileage isn't that much better, and then diesel costs at least 50 cents more per gallon (at least here in California.)
Reply | Report Abuse | Link to thisAnd has anyone who wrote this article ever filled up a diesel? First, don't slip in the slimey, oily concrete in front of the diesel pump, and then wear a silly little glove on both hands because the pump and nozzle are oily as the diesel fuel doesn't evaporate, and then when you're finished, get back in your car and smell the fuel on your hands no matter how careful you were.
Reciprocating pistons, and petroleum based fuels should be dead. Leverage our existing electrical grid and go electric, both with cars and high-speed rail.
Diesel is not making a come back in America. That is oil, coal, and natural gas pipe dreams. That stuff is too dirty and too expensive, and we don't have a grid set up for it. Only an anti-environmental idiot would buy a diesel car or truck. People who has a brain in their head will buy an electric car or truck.
Reply | Report Abuse | Link to thisUnfortunately in the state of California the rules are so restrictive that diesel truck no longer get better gas mileage than gas defeating that goal considering the diesel truck cost a third or more. Also the rules change so fast now that you have to replace the truck before it lifetime usage. Based on this a friend of mine that normally purchases all diesel for their paving company is switching to gas since it no longer makes financial sense. They used to buy four or more a year but not now.
Reply | Report Abuse | Link to thisgeojellyroll:
Reply | Report Abuse | Link to thisJust be quiet. People come here to read comments about the SA article, not another one of your angry, (often misinformed) tirades. Seriously. If you have something to contribute, then write. Otherwise, take your rage to the gym and work it out.
Audi has won 10 of the last 13 twenty-four hours of LeMans auto races with "diesel racecars", as for maintnance they are damb near maintnance free.
Reply | Report Abuse | Link to thismikedaddy: "for maintnance they are damb near maintnance free.'
Reply | Report Abuse | Link to thisI hope that was a joke. As for audi winning Le Mans auto races...therefore what? Jets fly largely on kerosene and go even faster. What does speed have to do with cost effectiveness or efficiency?
It's not about speed. They won Le Mans due to the greater efficiency of the diesel engine; fewer refuelling stops means more time lapping the competition. As for points made earlier regarding insurance and other costs etc. my old Merc 240D cost me about $30 Canadian a month for basic insurance, got about 35 Mpg, it had about 360,000 Km on the odometer and ran perfectly without any major engine work in its history. Oh and it cost me $900 to buy; it wasn't the cleanest car on the road I admit but for my first car it was pretty excellent.
Reply | Report Abuse | Link to thisNo, you're the inebriated one. Have you ever heard of geothermal, hydro or river energy; what about solar and wind? Oil, coal, and natural gas provides energy to fewer and fewer states anymore. A long time before electric cars and trucks become the majority in transportation, they all may be charged by solar. Coal, oil, and natural gas will no longer play a major part in charging your electric car. When I trade in my ICE car for an electric one, I am also going supply my garage with solar panels and a storage battery.
Reply | Report Abuse | Link to thisJames...coal is the daddy of electricity production in the USA, India, China, etc. It is INCREASING in use.
Reply | Report Abuse | Link to thisSo what? It can also be the mother, but that doesn't mean that we have to use it when we have other choices. Coal use in the U.S. had dropped from 70% to 50% in the last ten years because of solar and nuclear production. When electric cars start being mass produced, and they are starting now, oil and natural gas use will drop even further in percent of use than coal. China is leading the US in clean energy use and trying to completely eliminate coal use by 2050, or sooner. Fossil fuel is dead (no pun intended) and on its way back to the grave. A lot of people are preparing for a new clean 21st Century, and I am one of them.
Reply | Report Abuse | Link to this@JamesDavis actually we are not increasing nuclear production. The US has not produced a new Nuclear facility since the 70's. And with the introduction of 'Clean Coal' technology in the past decade, coal has actually increased in use in the US. China is not leading the US in clean energy. They are investing a lot more and will soon surpass us but we have a decent head start. A lot of people want a clean 21st Century myself and yourself included BUT that doesn't mean our country is taking the necessary steps to reach that goal. Our political leaders have been corrupted to much by the fossil fuel industry to make the kinds of changes other countries are towards a purely green and clean country.
Reply | Report Abuse | Link to this@geojellyroll
Reply | Report Abuse | Link to thisThe impressive point of audi winning motorsport races with a diesel is not that their cars are any faster. It is that they are more efficient. They won Le Mans because they made fewer fuel stops than all of their competitors, a major time advantage in any motorsport race.
Diesel carries a few advantages not discussed in the article. Namely, it is easier to refine. You achieve diesel before you achieve gasoline. You have to crack bonds in diesel (input energy) in order to get to gasoline, a light product. The energy invested over energy returned is greater with diesel. Further diesel carries more BTU's per gallon (it has a higher energy density) meaning you dont have to carry as much of it to travel and equivalent number of miles as you would on gasoline. The less weight you are carrying around the further your fuel will go.
Finally, your assertion that diesels have a higher maintenance cost per mile driven than gas cars is incorrect. My diesel powered jetta has a lower annual maintenance cost than my wife's gasoline civic.
Finally, modern heavy industry diesel's emit fewer tailpipe particulate emissions in PPM than they ingest through their intake tract in polluted cities like Los Angeles.
Not to mention my diesel is way more enjoyable to drive (city and highway) than my wife's civic ;)
This would be great. Imagine a Honda civic with a diesel engine in it - 50+ mpg. VW used to call this the Rabbit.
Reply | Report Abuse | Link to thisThe diesel engines can be a smaller CC than gas because diesel fuel has more energy than gas. Diesels have more torque than gas so those small engines would be better at starting cars moving. The engines would last longer than gas engines do now (diesels require heavier cylinder walls because of the extreme compression). Maintenance is reduced and much easier (no plugs, timing belts, plug wires, distributors, electronic ignitions, coils, etc.) to fool with. Just keep the fuel filter and oil filter changed. At some point, you can introduce natural gas and maybe hydrogen into the fuel mix, reducing fuel costs and decreasing emissions, but you could run diesel if you are not place you can get natural gas or hydrogen - the infrastructure is already in place. You can already do diesel-electric hybrids.
GM just screwed the market up by introducing a 350 gas engine made to run diesel that could not handle the compression of a diesel that would fail (blow apart) after a short time running diesel.
This is a great step into the alternative fuels. This would help the other technologies develop and get fueling stations established. I bought a car this weekend. I looked for a small diesel, but none were available. I got a small used car with no payment because they did not have what I wanted. Maybe they will have something available in my lifetime, and maybe I will be able to afford it!